1. Field of the Invention
The invention relates to the field of wireless communication, and more particularly to techniques for performing cooperative PLMN list generation or PLMN search on user equipment (UE) with dual RF transceivers in a mobile communication system.
2. Description of the Related Art
User equipment (UE) may be capable of communicating with different wireless networks by selecting different cells from a list of acceptable cells of several public land mobile networks (PLMNs). The user equipment generates a PLMN list by scanning all operating frequency bands to search for wireless networks of all supported radio access technologies (RATs), such as universal mobile telecommunications system (UMTS) networks, and global system for mobile communication (GSM) networks. For example, when the user equipment is turned on, the user equipment may perform a manual search or an automatic search to generate a PLMN list including a home PLMN (HPLMN) and other PLMNs. The PLMN list may be provided for normal cell selection or recovery communication from a limit service area or no service area. Further, when camping on a specific PLMN, the user equipment is required to periodically perform a home PLMN (HPLMN) search or a higher priority PLMN search to look for a more suitable PLMN with higher priority or better signal quality than the specific PLMN. However, the process of searching all supported RATs is substantially time period-consuming, especially when the user equipment moves among cells.
Moreover, since the user equipment according to the prior art is supplied with one single RF transceiver, the process of PLMN list generation or PLMN search may be suspended or not allowed when the user equipment enters into a dedicated mode, such as establishing a dial-up connection, transferring data packets, answering an incoming voice call, or performing a WAP/Internet browsing application. In such situations, the PLMN list generation or PLMN search operation would be suspended, and the intermediate list or search results would be discarded. Inevitably, the user equipment would have to restart the PLMN list generation or PLMN search, thereby deteriorating the general performance of the user equipment and leading to bad user experience.
Therefore, a need exists for user equipment capable of performing PLMN list generation or PLMN search more reliably and efficiently so as to improve the general performance of the user equipment.